Deleting customers now gives you a clear choice about their history, and course clash warnings behave properly.
- The delete confirmation now shows a Keep records checkbox, ticked by default, instead of asking you to type to confirm. Leave it ticked to remove the customer but keep their history, or clear it to remove their records too.
- The same choice appears when you delete several customers at once from an admin list, so single and bulk deletion behave the same way.
- When you save course dates and times and the new times clash with another class, the loading spinner now closes first, so you can read and respond to the warning instead of it being stuck behind the spinner.
